How to disable the conversion of SMS to MMS on Xiaomi

Owners of Xiaomi, Redmi and POCO smartphones often face the unpleasant situation: you send a normal text message, and in the delivery report or in the details of traffic consumption you see that it went as a multimedia message. This leads to a write-off of money for Internet traffic or MMS rates, which is especially true in roaming or in the absence of data packets. MIUI and HyperOS are set up by default for maximum functionality, sometimes at the expense of saving the user’s budget.

The main reason for this behavior is the Messages app settings, which often uses the RCS protocol or just an aggressive long text conversion policy. When you write a message longer than a certain number of characters or add an emoji, the phone automatically switches the message type from SMS to MMS. Understanding the mechanics of this process will allow you to take control of costs and return the standard behavior of the system.

In this guide, we’ll look at all the possible ways to solve the problem, from simple menu switches to deep settings in the system application. You’ll learn how to distinguish between standard and multimedia, and what hidden features can interfere with normal operation. On some global MIUI firmware, the option to disable conversion is hidden in the “Advanced” menu, which can only be accessed through a sequence of actions.

Why SMS is turning into MMS on Xiaomi smartphones

Short Message Service (SMS) technology is limited to 160 Latin characters or 70 Cyrillic characters in one segment. If your text is longer, it breaks down into several parts. However, modern Xiaomi smartphones are looking to improve the user experience by combining long texts into one message. To do this, they use the MMS protocol (Multimedia Messaging Service), which was originally designed to transfer pictures, but is now used for long texts.

In addition, many carriers and manufacturers are adopting the RCS (Rich Communication Services) standard, which is positioned as a replacement for the classic SMS. In the Messages app from Google or the MIUI system application, this feature can be activated by default, in which case the message leaves over the Internet, even if you did not add photos. This is convenient for high-quality communication, but is categorically not suitable for those who want to save traffic or do not have a gigabyte tariff.

Another reason could be that text has special characters or formatting that the system interprets as multimedia content, such as inserting a business card or geolocation automatically changes the type of message, and it's important to understand the difference: SMS is charged by the number of messages, and MMS is charged as Internet traffic or at a separate, more expensive operator tariff.

• 📱 Message length: Exceeding the limit in 3-4 segment often triggers conversion.
• 🌐 Protocol RCS: Google Messages’ Chat feature uses the internet.
• 🖼️ Media attachments: Any photo, video or audio changes type to MMS.

⚠️ Warning: If you don't have unlimited internet, sending MMS roaming can cost tens of dollars per message.Always check the type of message before sending it abroad.

Configuring the system application "Messages" MIUI

In the standard Xiaomi app, which often has a blue or green envelope icon, settings can be hidden quite deeply. MIUI is prone to minimalism, so some important switches are in sections where the user rarely looks. First, you need to open the application itself and find the settings menu, usually hidden behind three dots in the corner of the screen or behind the gear icon.

Inside the settings menu, look for the section associated with Multimedia Messages or MMS Settings. This can be the Auto Convert or Convert to MMS switch. If this option is not explicitly available, try to find Saving Mode or Standard Mode. Different versions of the HyperOS shell may have different locations, but the logic remains the same: you need to find a ban on using data for messages.

You should also pay attention to attachment size settings, and even if you don't send a photo, the system can reserve space for it, which changes the header of the data packet, and reducing the attachment limit to a minimum or completely disabling the ability to attach files can force the system back to SMS mode.

If you can't find the right switch, your firmware version may have a stripped-down menu, in which case try resetting the app to factory settings. This will return all settings to the "out of the box" state, which sometimes removes the erroneous configurations imposed by updates. Go to Settings → Apps → All Applications → Messages → Clear and select "Reset".

Disabling conversion in Google Messages

Most of today’s Xiaomi global smartphones come pre-installed with Google Messages. It’s a powerful app, but it aggressively promotes chat features (RCS) that require the internet. To turn off conversion, the first thing you need to do is go to the app’s settings by clicking on the profile avatar in the top right corner and selecting Message Settings.

In the section “Chat (RCS)» You need to turn off the "Enable Chat" function. As long as this switch is active, the phone will try to send a message over the Internet using your phone. IP-Address and mobile data: Once disabled, all messages will be sent exclusively over the cellular network as classic SMS or MMS, depending on the content.

Next, check the Multimedia Messages section, which contains limits on file size and image quality, and set a size limit to a minimum (e.g., 300KB or 100KB) that won’t ban MMS altogether, but will make sending large files impossible without your explicit consent, which serves as an additional filter.

It is important to note that after updating the application, settings may reset. Periodically check the status of the Chat function. If under the text input field you see the words "Chat" instead of "Text message", then conversion is still possible. The switch must be inactive to ensure that only cellular channels are used.

Limiting mobile traffic for messages

A radical but effective way to prevent SMS from leaving MMS is to completely ban the use of mobile Internet for the Messages app. If the application does not have access to the network, it will physically not be able to send the message as an MMS, even if the settings in the application allow it. The phone will simply give an error or wait for Wi-Fi to appear (if there is one), but in the mobile network conditions it will switch to SMS.

To implement this method, go to the phone's general settings Settings → Apps → All apps. Find Messages (or Messages) in the list. Select Data Use or Network Connections. Here you'll see switches for Wi-Fi and Mobile Data. Leave Wi-Fi on (if you want to receive messages at home), but turn off the Mobile Data slider.

This method has one caveat: if you have RCS enabled, messages from other RCS users may not arrive until you connect to Wi-Fi. However, for outgoing messages, this works perfectly: the phone will try to send MMS, will not gain access to the network, and will usually automatically reclassify the message into a normal text SMS or issue a warning about the need for data, suggesting that it be sent as an SMS.

⚠️ Note: Disabling mobile data for the Messages app may result in you not being able to receive images from contacts using iMessage or RCS, until you turn on the Wi-Fi.

Use of third-party applications for SMS

If the standard tools of Xiaomi and Google don’t work, or the interface seems too confusing, you can always use third-party developers. Apps like Textra, Pulse SMS or Better SMS give the user full control over every byte of data sent, and they don’t have hidden conversion algorithms that you don’t know about.

For example, Textra has a separate settings menu for MMS. You can explicitly specify “Never send MMS” or set a hard size limit of 1 KB. In addition, these applications often have a more intuitive interface for switching between modes. SIM-You can set up the rule: SIM card 1 - SMS only, SIM card 2 - MMS is allowed».

Installing a third-party application requires permissions to access contacts and SMS. This is standard procedure for messengers. Once installed, Android will ask which application to use as default for SMS. Choose the installed application, and it will completely intercept the management of messages, ignoring the settings of the system application MIUI.

Additional settings and troubleshooting

Sometimes the problem isn't with settings, but with cache or network error. If you've all turned off but the message still leaves as an MMS, try clearing the cache of the Messages app and Google Play service. Accumulated temporary files may contain old configurations that conflict with the new settings.

It is also worth checking the settings of the access point. APN - Your operator. → SIM-maps and mobile networks → SIM-card (yours) → Access points (APN). Select an active point and check the field. MMSC. If it's full, the phone knows where to send the media, and in theory, cleaning that field (if the system allows you to save the settings) can completely block the ability to send MMS, leaving only SMS.

Do not forget that some operators impose services "Super-SMS" or similar, which at the network level convert long texts to MMS. In this case, no settings of the phone will not help - you need to contact the operator's support service with the requirement to disable the service of conversion of messages.

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Before traveling abroad, be sure to make a test call and send an SMS to a friend's number to check if the money for the MMS was written off.

Frequently Asked Questions (FAQ)

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Disabling mobile data completely for the Messages app is the most reliable way to ensure that no message leaves as an MMS, but it will limit chat functionality.